The invention relates to an active, divided stabilizer for a motor vehicle having an incorporated pivot motor.
Dividing a motor vehicle stabilizer into a first stabilizer part assigned to the suspension of the left wheel of a vehicle axle and a second stabilizer part assigned to the suspension of the right wheel of this vehicle axle is already known. If these stabilizer parts are pivotable in relation to one another around their shared longitudinal axis, significantly increased roll stability may be achieved in relation to chassis having one-piece roll stabilizers, if a suitable pivot motor is provided between the two stabilizer parts, which pivots these stabilizer parts in relation to one another as needed on the basis of a suitable activation.
A pivot motor comprises at least one motor and a mechanical transmission. A stabilizer is thus obtained whose two stabilizer parts, which are connected to one another by the pivot motor, may be pivoted in relation to one another in a targeted way, so that a desired stabilizer torque is generated, which then prevents the rolling of the vehicle structure. Such a stabilizer is described in German Patent Publication No. DE 198 46 275 A1.
Stabilizers for active roll stabilization thus comprise one or more torsion springs having an incorporated hydraulic, pneumatic, or electromotive actuator. For the implementation of roll stabilization, on the one hand, the guide behavior of the actuator and, on the other hand, the behavior of the system in relation to external interfering influences, are essential for satisfactory function. The influence of an external interfering excitation is to be regulated out actively by the system. This may be performed with a hydraulic actuator, for example, using a pressure regulating valve. The interfering influence is reduced by the equalization of the hydraulic pressure. A proportional valve, which is usable, for example, may operate purely passively, so that no active regulator intervention has to occur.
In electrical roll stabilization systems, as described, for example, in German Patent Publication No. DE 100 02 455 A1, and in German Patent Applications of the applicant having the reference numerals DE 10 2005 031 036 and DE 10 2005 031 037 (no prior publication), an active regulator intervention is necessary for the reduction of the interfering influence. For this purpose, it is necessary to detect the interfering variable using measurement technology. Up to this point, deriving the influence of the interfering variable from the signals of ride height sensors is known. Piezoelements are suggested in German Patent No. DE 197 05 809 C2.
The use of two ride height sensors per axle is preferable for ascertaining the interfering variable influence via ride height sensors. Only in this way may the interfering influence on the stabilizer, which is to be regulated out using the actuator, be ascertained. The detected signals of the sensor are composed of the wheel-related excitation and the oscillation excitation of the body. A complex analysis of the signals to be able to calculate the acting interfering variable results therefrom. Furthermore, high requirements are placed on the precision and resolution of the ride height sensors by the interfering variable ascertainment.
The object of the invention is to avoid these disadvantages as much as possible.
According to the invention, a divided motor vehicle stabilizer having an incorporated pivot motor for roll regulation, which comprises at least one displacement drive made of motor and transmission and one housing, at least one housing part being connected to an associated stabilizer part for torque transmission in such a way that the housing part has an axially oriented, central indentation, into which the stabilizer part extends essentially up to its end, and the connection for torque transmission between the housing part and the stabilizer part associated therewith is located therein, is characterized in that a sensor for detecting the torsion angle of the stabilizer part is attached to the housing part, whose encoder is fixed on the stabilizer part or vice versa.
In an advantageous embodiment of the invention, the sensor delivers measured values which are used to activate the motor, in particular via a control unit. It is particularly advantageous if the control unit ascertains values corresponding to the torsion torque applied to the stabilizer part from the measured values of the sensor.
A further advantageous embodiment of the invention provides that the motor is an electric motor.
An interfering variable acting on the active roll stabilization causes a change of the torque in the passive torsion spring of the stabilizer. A direct detection of the torsion torque may thus be used directly as an input variable for regulating out the interfering variable acting on the actuator. This torsion torque of the passive stabilizer part may be detected using conventional torque sensors, for example, via strain gauges. However, the conventional torque sensors have the disadvantage that they either have too little sensitivity to the engaging torque or are too complex and costly to implement. For this reason, the torque to be detected is ascertained via the torsion angle of the stabilizer.
Greatly varying sensor principles are usable for the angle and/or position detection, namely optical, capacitive, electromagnetic, or ohmic. In particular, inductive position detection may be implemented simply and robustly for the application described here. The position change of the encoder is measured on the basis of the pivot angle caused by the torsion torque of the stabilizer part plunging into the housing.
It is advantageous that the interfering torque is detected directly by detecting the pivot angle directly at the torsion spring of a stabilizer part. The conditioning of the sensor signal may thus be performed simply. The regulator structure may be constructed simply and robustly. Only one sensor is required per axle. Moderate requirements are placed on the sensor in regard to precision and resolution. For this reason, cost-effective sensors may be used. The employed measuring method is a contactless principle, which is to be evaluated as optimal in regard to service life and wear.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.